My invention relates to an overdrive protection circuit, and particularly to an overdrive protection circuit that limits the gain of a broadband frequency amplifier in a power line carrier system.
In previous power line carrier systems, the gain of a broadband frequency amplifier was controlled by a feedback loop using the magnitude of a pilot frequency signal. When the broadband frequency amplifier was turned on, or when the feedback loop was switched into the circuit, large magnitude signals in the broadband of frequencies tended to overdrive the amplifier. As a result, the pilot frequency signal was suppressed, and the gain of the amplifier was kept too high so that the signals were distorted, or so that those operations in the power line carrier system that depended on the pilot frequency signal were faulty.
Accordingly, a primary object of my invention is to provide a new and improved overdrive protection circuit for power line carrier systems.
Another object of my invention is to provide a new and improved circuit for use with power line carrier systems to maintain the gain of a broadband frequency amplifier at the desired level, even though the pilot frequency signal may be lost or suppressed.
Another general object of my invention is to provide a new and improved circuit that prevents overdrive and thus improves the reliability and quality of a power line carrier system.